The FAVORIT trial has several design features that enhance its ability to address the question of whether lowering total homocysteine (tHcy) concentrations can reduce the risk of CVD among patients with chronic kidney disease (CKD). At the current three month rate of 152 randomizations per month FAVORIT will complete enrollment well within the target deadline of January 31, 2007 The sample size (n=4000;n=3621 recruited as of July 5, 2006) is the largest to date for a trial with our objective, the planned follow-up time through June 2011, is the longest, and preliminary screening data suggest baseline tHcy levels are higher in FAVIORIT than in trials conducted among non-renal disease populations. Assuming the projected FAVORIT event rate for CVD among controls occurs, the trial will remain well-powered (i.e., 0.87) to discern a moderate 20% reduction in events (if achieved) with active tHcy-lowering treatment. The FAVORIT trial provides a unique opportunity to obtain biologic specimens on a large cohort of stable kidney transplant recipients at baseline and annually throughout 4.5 to 9 years of proposed follow-up. Appropriate consent has been obtained to make specimens available for ancillary studies and many of the specimens have already been transferred to the NIDDK Specimen Repository. For use in ancillary studies, the following specimen types are being collected: EDTA plasma, buffy coat, red blood cells, serum, sodium citrate plasma, and urine. These specimens have bar-coded'ID labels without any personal identifiers. Regardless of whether or not the tHcy-lowering intervention in FAVORIT significantly reduces CVD event rates, monitoring the trial cohort of 4000 chronic stable renal transplant recipients, ranging from a minimum follow-up of 4.5 years, to a maximum of 9 years, will provide unique data on arteriosclerotic CVD outcomes, and (potential) antecedent CVD risk factors, in this patient population. Complementary ancillary studies under review will further address the interrelationships between initial renal function and degree of albuminuria, and/or serial changes in these parameters, with both renal and CVD outcomes in the FAVORIT cohort. An ongoing NIH-funded FAVORIT ancillary study (R01 DK65114-03 "FAVORIT Ancillary Cognitive Trial [FACT]" is already providing unprecedented data on cognitive function and affect in chronic renal transplantation.